Immunosuppressants, nucleic acid antagonists, antimetabolites, etc., are used in the medicinal treatment of autoimmune diseases today. Anti-inflammatory agents, anticoagulants, etc., are also used in the symptomatic therapies of the diseases. The effects of these agents are, however, not yet sufficient.
It is known that the immunosuppressants have side effects of provoking diabetes, renal disorders, infectious diseases, etc. Also the use of the nucleic acid antagonist or antimetabolite is frequently accompanied by side effects such as hepatic disorders and medullary disorders. Thus the medicinal treatment of autoimmune diseases is so far very insufficient.
It has been demanded to develop a remedy for autoimmune diseases which acts on the immune system and which has a function mechanism different from that of conventional drugs for the diseases and less serious side effects.